Carriage driving and hammer returning means



Dec. 25, 1934. A. E QSWALD 1,985,419

CARRIAGE DRIVING AND HAMMER RETURNINGJMEANS Filed July 7, 1951 4 Sheets-Sheet 1 INVENTOR A/fredt. 0514 0/4 4/Zag ATTORNEY Dec. 25, 1934. E.OSWALD CARRIAGE muvma AND HAMMER RETURNING MEANS Filed July '7, 1951 4Sheets-Sheet 2 gm h ' INVENTOR Alfred t7 OSWd/d ATTORNEY Dec. 25, 1934.A. E. OSWALD 1,985,419

CARRIAGE DRIVING AND HAMMER RETURNING MEANS Filed July 7, 1931 4Sheets-Sheet 5 L. Oswald A ITORNEY Dgc. 25, 1934. A. E. OSWALD CARRIAGEDRIVING AND HAMMER RETURNING MEANS Filed July 7, 1931 4 Sheets-Sheet 4 IINVENTOR Alf/e45 OJWd/fi.

BY )W iMM ATTORNEY Patented n e. 25, 1934 PATENT OFF/ICE 1,985,419CARRIAGE DRIVING AND RETURNING MEANS Alfred E. Oswald, Hackensack, N.1., assignor, by

mesne assignmenta'to Ralph C. Coxhead Corporation; New York, N. Y., acorporation of Delaware Application July'l, 1931, Serial No. 549.170

8 Claims.

This invention relates to typewriting machines and more particularly toimproved power means for driving the carriage and for restoring theprinting hammer against the action of its actuating spring. The.invention is shown as applied to a varityper writing machine and is inthe na -j connected in circuit with a normally open switch,-

the latter being operable by any one of the key levers to close it andthus energize the solenoid to cause its actuation. The solenoid operatesa reciprocatory device including a lever, to which is connected thedriving spring, and upon which is pivotally supported a pawl toco-operate with a ratchet wheel, associated with the escapement wheel,to assist in driving thelatter, said escapement wheel being connected inthe usual manner through a dog carrying lever with the printing hammer.V s

A feature of the present invention is to automatically break thesolenoid circuit after each operation thereof so as to prevent heatingwhich may otherwise result from carelessly holding the key leverdepressed. l

Another feature of the invention relates to the construction ofthesolenoid so that it may be used for alternating currentor directcurrent and for different voltages as, for example, 110 volts or 220volts. j l I Other features and advantages will hereinafter appear.

In the drawings which form part of the speci fication, I a

Fig. 1 is a sectional side view of the machine taken on the line 11 ofFig. 4;

Fig. 2 is a detail sectional view taken on the line 22 of Fig. 4 showingthe switch and its 6f the blocks forming ported in a rear cross-bar 3'7of the main frame Fig. 4 is a rear view of the machine, parts beingbroken away;

Fig. 5 is a diagram of the electric circuit;

Fig. 6 is a fragmentary rear view showing the solenoid operating to cockor set the power means and showing the switch about to be opened;

Fig. 7 is a horizontal section through the solenoid;

Fig. 8 is a vertical section through the solenoid taken on the line 88of Fig. 7;

Fig. 9 is a detail view of a modified form of plunger for the solenoid;and

Fig. 10 is an end view of the modified form of plunger.

Similar characters refer to similar parts throughout the several views.

The invention is shown applied to a varityper writing machine whichincludes a main frame 20 to which is secured a track 21 upon which acar- 20 riage 22 is mounted to travel back and forth transversely of themachine. The carriage is provided with a bar 23 which co-operates withthe track 21 through anti-friction rollers or balls 24 to guide saidcarriage. The carriage is further guided by 5 a bar 25 at its upper endco-operating with a roller 26 mounted on the main frame 20.

The carriage is urged in a letter feed direction by a carriagepropelling means or spring drum 30 (Figs. 3 and 4) rotatably supportedby a shaft 31 30 (Fig. 4) on the main frame 20; the spring drum beingconnected to the carriage by a strap or draw band 32. Letter feedmovements of the carriage are effected by escapement mechanism,indicated generally by the numeral 33, which is actuated at eachoperation of the key levers 34.

The escapement mechanism includes a pinion 35 to be engagedby a rack350: on the carriage, said pinion being connected to a shaft 36 sup- 40and a lug 38 of said frame. An escapement wheel 48 is rotativelysupported on the escapement shaft 36 and has secured thereto a ratchetwheel 49. The ratchet wheel 49 is engaged by a pawl 51 piv- 45 oted by ascrew 52 on an arm 53 secured to a hub 54, the latter being fastened tothe shaft 36. Thus by this connection the escapement wheel is connectedto be rotated by the carriage through the medium of the shaft 36 inaletter space direction. 50 Said escapement wheel is normally heldagainst rotation by a loose dog 56 pivoted by a stud 5'7 on a lever 58pivoted on the escapement shaft 36, the downward movement of the lever58 being limited by a stop 59 of a fixed bracket 60 secured to the Irear bar 37 of the machine frame. While the carriage is being returnedthe pawl 51 rides freely over the teeth'of the ratchet 49 against theaction of a spring 61 connected between an car 62 of the pawl 51 and apin 63 on the arm 53. A spring pressed pawl 64 (Fig. 4) prevents,backward rotation of the escapement wheel.

Toactuate the escapement mechanism 33 and thus feed the carriage at eachprinting operation, the key-levers 34 when actuated about fulcrums 65,engage a universal bar 66 of a frame 67 to swing the latter about afulcrum 68. An arm 69 of the frame 67, when the latter is actuated,swings downwardly to actuate a dog rocker 70 through the medium of a setscrew 71 engaging a tall 75 of the dog rocker to carry a fixed dog 73into engagement with the teeth of the escapement wheel 48.

The dog rocker 70 is provided with an arm 74 having a slot 75 into whichextendsa pin 76 from the loose dog 56, whereby the loose dog is swungout of engagement with the escapement wheel; the dog carrying lever 58being connected to a printing hammer 77 by means of a stud 78 to beactuated thereby during a printing operation of said hammer which isactuated in a manner hereinafter described. As the pin 76 travelsupwardly in the slot 75 the dog 56 is guided into the path of the nextsucceeding tooth of the escapement wheel. Subsequently the dog rocker 70is brought back to normal upon the return of the arm 69 to disengage thedog 73 from the escapement wheel, whereupon the escapement parts and theprinting hammer 28 are restored to normal.

The printing instrumentalities include a type carrier or shuttle 80having types 81 with which a head 82 of the hammer 77 co-operates toprint against an interposed work sheet 83, the work sheet being fed upand down by suitable feed rollers 84 and 85 supported on the carriage22.

The type shuttle 40 is curved to conform with acylindrical anvil 86 bywhich it is carried through the medium of a thin flange 87 extendingthrough a slot 88 in said anvil.

To actuate the type shuttle 80 the flange 87 has connected thereto alever 89 secured to a sleeve 90 to rotate about the axis of a shaft 91;the sleeve 90 being supported on a bar 92, of the main frame, on whichit is maintained by a screw 93 engaging a flange 94 at the lower end ofthe said sleeve.

The shuttle actuating lever 89 may be actuated, from a. centralposition, in opposite directions by either of two arms 95, about theshaft 91, said arms being actuated, one at a time, in a mannerhereinafter described, to carry the selected type of the shuttle 80 tothe printing point, the types being accurately positioned by means ofindexing pins 96 operable by the key levers 34 to project their upperends into the path of the shuttle lever 89 to arrest the latter.Subsequently the hammer is actuated, under the control of the escapementmechanism, by a spring 96,said hammer being secured to a shaft 97, Fig.3, supported by pivot screws 98 on the main frame 20.

Each 01' the arms which operates the shuttle actuating lever 54 formspart of a frame 97, each frame being supported to swing about a pivot 98on a fixed bracket 99. Each frame 97 also includes a bar 100 extendingtowards the middle of the machine and over the key lever '34 to one sideof the middle of the machine, so that if any one of the key levers isoperated the associated one of the frames 97 is actuated thereby againstthe action of a return spring 101. The upper end of the arm 95 is thusswung rearwardly to actuate thelever 89 and shuttle 80 to select thetype as above described. The arms95 may engage the lever 89 directly, ifdesired, or they may engage a resiliently supported slide 102 thereonlike that shown in the application of Frank H. Trego, Serial No.412,651, filed December 19, 1929, which slide permits a slight movementof frame 97, after the arm 89 has been arrested, to actuate theescapement mechanism.

When the escapement is operated the release of the printing hammer iseflected from the escapement wheel by the actuation of the dog rocker 70as previously described. It is then actuated, by the spring 96 connectedthereto, to print.

The release of the carriage may be effected as in the abovementionedspaloss application by means which includes a release arm 105connected to a thrust rod or plunger 106 (Figs. 1 and 4) which isslidably supported on the hub 54 at the end of the escapement shaft 36.The inner end of said plunger is provided with an annular cam 107 which,when the plunger is moved inwardly, engages the ear 62 of the pawl 51 toswing the pawl 51 about the pivot 52, in any position which it mayoccupy about the axis of the escapement shaft, to disengage said pawlfrom the ratchet. Thus the carriage may be released from the escapement.

The means which assists in returning the printing hammer includes aspring (Fig. 4) one end of which is connected to a bracket 127 securedto the rear bar 37 of the machine frame by screws 128. The other end ofthe spring is connected to a lever 129 pivoted by a stud 130 on saidbracket 127, the spring tending to rock the lever 129 in a clockwisedirection to rotate the ratchet 49 and the escapement wheel 48 securedthereto in the same direction through the medium of a pawl 131 supportedon the shoulder of a headed stud or screw 132, the pawl 131 being heldin contact with the ratchet 49 by a spring 133.

It will be understood that whenever the lever 129.is actuated in acounterclockwise direction, (Fig. 4) the pawl 131 is cooked as in Fig. 6against the action of the actuating spring 125, said pawl snapping overone of the teeth of the ratchet 49. Thus the spring 125 is energized ateach actuation of the lever 129 in this direction which occurs at eachletter space movement of the carriage and after the printing operation,and is caused by means hereinafter described, under the control of thekey levers 34. After the reciprocatory means including the lever 129,pawl 131 and spring 125, has been cocked, it is released and rotates theescapement wheel to restore the printing hammer 77, against the actionof its spring 96, through the medium of the dog 56 and the dogsupporting lever 58.

To actuate the'lever 129 and thus increase the strength of the spring125 there is provided an electromagnet or solenoid 135 held on the rearbar 37 of the machine frame by a strap 136 secured to said rear bar byscrews 137, and a bracket 136 secured to an end piece 139 of thesolenoid by screws 140, said bracket 138 being secured to the machineframe by screws 141. The solenoid when it is energized, as hereinafterdescribed, sucks in a plunger 142 to draw on a link 143 pivotallyconnected thereto by a pin 144. The other end of the link 143 isconnected to the lower end of the lever 129, by a shouldered screw 145,to actuate the lever 129 in a counterclockwise direction when thesolenoid is energized.

To limit the movement of the plunger 142, and its connected parts, whenactuated by solenoid 135, the lever 129 has a lip 146 to engage a stop147 secured to the bar 37 of the main frame.

The operation of the solenoid is effected by a normally epen switch 150(Fig. 4) which may be closed at the proper time by any one of the keylevers 34 to cause an electric current to flow from a source of supply151 (Fig. 5) through conductor 152, main switch 153, conductor 154,resistance 155, conductor 156, solenoid 135, conductor 158, switch 150,conductor 159. to ground 160. When the actuation of the solenoid is thuseffected the escapement operating mechanism including the pawl 131 iscocked thereby as above described. I

The switch 150 includes a contact spring 163 to which is connected theconductor 159 and a contactspring 164 to which is secured the conductor158. Said contact springs are supported in slots 165 and 166 formed inthe oppositely disposed faces of blocks 16'! and 168 of insulatingmaterial, said blocks being secured to-the rear bar 37 of the main frameby a screw 169.

To close the switch 150 there is provided on the arm 69 of the universalbar frame a bracket 1'70 having secured thereto a finger 1'71 which,whenever the universal frame 6'7 is operated by the key levers 34, asabove described, flexes the contact spring 164 downwardly against thecontact spring 168 and thus close the switch 155, whereupon the solenoid135 operates to cock the pawl 131 against the action of the spring 125as previously described.

Provision ismade to automatically cut off the current to the solenoid135' upon the completion of its operation so as to prevent heating ofthe solenoid which would otherwise result when the active key lever iscarelessly held depressed. To this end there is adjustably secured tothe link 143, which is operated, by the solenoid plunger 142,aprojection by a screw 176, said projection to engage the finger 171which is resilient, as in Fig. 6 to move the free end thereof from .thecontact spring 164 to allow the latter to return to normal, thus openingthe switch 155 to tie-energize the solenoid 135. It will be understood,see Fig. 6, that the pawl 131 has already reached its cocked positionbefore the switch is opened, so that the spring 125 is ready tofunction, through the medium of said pawl and the ratchet 49 to returnthe printing hammer as previously described. Upon the return of theuniversal bar 66 to normal, the finger 1'71 snaps back into place overthe end of the contact spring 164.

To prevent the current from flowing into the finger 171, there issecured to the upper face of the contact spring 164 a block 177 ofinsulating material which projects slightly beyond the end of saidcontact spring to prevent touching the 'finger 164 when the latter ispushed off the contact spring.

The operation of the switch is semi-automatic since the closing thereofis performed manually by means under the control of the key levers, andthe opening thereof is effected automatically by the solenoid, theoperation of which is brought about by said switch.

To prevent arcing and freezing of the contacts of the switch 150 thereis connected in parallel with the switch a condenser 180 by conductors181 and 182. Said condenser acts to momentarily absorb the energy thatwould otherwise occur across the contact points while the switch isopening.

The solenoid is of the iron-clad plunger type. It comprises a sleeve orbushing 185 (Fig. '7) upon which is wound a. coil 186 composed ofenameled, single silk insulated soft copper wire. the coil extendingfrom one end to the other of the sleeve, only a few of the windings ofthe coil being shown at each end thereof. Two discs 187 of insulatingmaterial, such as fibre, form with the sleeve a spool to carry the coil186. The spool is contained within a cylindrical shell 188 of steelwhich shell is closed at its ends by metal discs 139 and 189 also ofsteel, said discs being secured to the shell 188 by pins 190. A core 191is contained within the sleeve to form with the plunger 142 discs 139and 189, and shell 188, a path for the magnetic flux. The bushing 185 iscomposed of brass or any other non-magnetic material to avoid frict'onof the plunger 142 which would otherwise be produced.

The core 191 is adjustable axially of the bushing by a screw 192,secured to said core, and is threaded into the bracket 138 so that uponthe rotation of said screw the core may be adjusted to its properposition. The core is held in its adjusted position by a lock nut 193 onthe screw 192 and bearing against the face of the bracket 138.

The plunger 142 is provided at its end with an escutcheon pin 194, ofbrass, to prevent anypossibility of sticking to-the core 191, due toresidual magnetism, which may otherwise result if the end of the coreand plunger touch each other.

Provision is made to prevent eddy or secondary currents which wouldotherwise be generated in the solenoid when it is used on alternatingcurrent. Said current if allowed to exist would greatly heat and thuslower the efliciency of the solenoid. The eddy current opposes theprimary current through the solenoid winding and thus reduces themagnetic pull on the plunger 191. Such eddy or secondary current wouldput an extra load on the coil 186 and would result in more currentconsumption.

To prevent said eddy currents all of the metal parts, bushing 185, discs139 and 189, and shell 188, plunger 142 and core 191, are provided withslots 196, 197, 198, 199, and 200, respectively. It will be understoodthat the slot 196 is near the upper sides of the bushing to prevent oilfrom dropping into the coil if someone should attempt to oil orlubricate the plunger of the solenoid.

The plunger 142 and the core 191 are solid and are provided with slots199 and 200 respectively. To produce a similar effect, that ofpreventing eddy currents, they may each be constructed as the plunger201, illustrated in Figs. 9 and 10. which is composed of laminations 202held together by rivets 203.

A shading coil 205 comprising a semi-circular tube of copper is securedto the end of the core 191, and causes the solenoid to operate on splitphase, and is effective when the solenoid is used on alternatingcurrent. With the shading coil there is produced an effect similar to atwo phase circuit as if the solenoid has a duplicated winding. When onefrequency of a single phase circuit produces magnetism in the solenoidthe shading coil chokes back some of this magnetism and thereby producesmagnetism of its own when the original pliase cycle is reversed throughzero. In other words the magnetism produced by the shading coil is 180degrees out of phase. This produces a more uniform magnetic pull anddecreases the magnetic hum which is due to the alternating current. Itwill be understood that the shading coil functions only on A. C. currentand does not interfere when D. C. current is used.

The resistance 155 is detachably connected in the circuit so that it maybe substituted by any one of a plurality of similar resistances, eachresistance having a different ohmic value to compensate for differentvoltages and D. C. and A. C. current. Each resistance comprises asuitably insulated winding 210 (Figs. 1, 3 and 4) the ends of which areprovided with metal tips or ferrules 211 to be received in resilientclips 212 and 213 extending from brackets 214 and 215 secured to a block216 of insulating material suitably i'astened to the machine frame; thebrackets 214 and 215 having secured thereto the conductors 154 and 156.

An object of using a resistance 155 in series with the solenoid isprimarily to allow the line voltage to overcome the inductance oi thesolenoid more quickly and to keep the current at a safe fixed value. Theinductance exists all the time while the A. C. current is flowing;consequently a lower resistance is used than with D. C. current. On D.C. current just as soon as it is turned on the rise in magnetism chokesback the solenoid current, causing the current to rise from zero to amaximum in a longer interval of time than it would require iiresistances of the same ohmic value were used in place 0! the solenoidwinding. Thus it will be understood that the voltage drop across theseries resistance and the inductance of the solenoid winding willautomatically adjust itself advantageously, whereas the voltage dropacross the solenoid winding will at first (on start of current) be atits maximum and gradually fall, that is the voltage will drop across thesolenoid until the current reaches a maximum. The advantage of thisarrangement is that the same solenoid may be used for the variousconditions or voltage and kind or current.

Although some of the devices abovedescribed may not in themselves benovel, it should be understood that there is a decided advantage ofusing in combination the solenoid with a shading coil therein, andconnecting the solenoid in series with a resistance to give an automaticvoltage control over the inductive winding of the solenoid, use of acondenser in the circuit to prevent sparking and freezing of the switchcontacts, and the use of a semi-automatic switch whereby the current iscut off to prevent heating of the solenoid when an operator carelesslyholds down an actuated key lever.

While certain preferred embodiments of the invention have been shown anddescribed, it should be understood that changes in the form,arrangement, proportions, sizes and details thereof may be made withoutdeparting from the scope or the invention as defined in the appendedclaims.

I claim:

1. In a typewriting machine, the combination of key levers, aselectively settable typecarrier, means operable by said key levers toeffect the setting of said type carrier, a hammer to cooperate with saidtype carrier, means operable by said key levers to eiiect the actuationof said hammer, spring actuated means to return said hammer, electricmeans, means operable by said key levers to render the electric meansefiectlve to cock said spring actuated means at each op-' eration of anyone oi the key levers, and means whereby the electric means may berendered ineflective after the spring has been cocked and while the keylever is still in its operated position.

2. In a typewriting machine, the combination of keylevers, a selectivelysettable type carrier,

or key levers, a printing 1,ess,41a

means operable by said key levers to efl'ect the setting of said typecarrier, a hammer to cooperate with said type carrier, means operable bysaid key levers to effect the actuation of said hammer, operating means,an electro-magnet the actuation of which is effected by the key leversto cock said operating means at each actuation of any one of said keylevers, means to automatically render said electro-magnet ineflectiveindependently of the key levers after the operating means has beencocked so as to avoid heating of the electro-magnet if the return of thekey lever is delayed, and means actuable by the operating means to cooksaid hammer.

3. In a typewriting machine, the combination of key levers, a printinghammer, means operable by said key levers to effect the actuation of thehammer, spring actuated means to return said printing hammer,electrically operated means including an element to cook the springactuated means, means operable by the key levers to render theelectrically operated means eilective at each depression of any one ofthe key levers, and means associated with said element to render theelectrically operated means inactive independently of the activeone ofthe key levers after the spring actuated means has been cocked therebyso as to prevent heating of the electrically operated means if thereturn of a keylever is delayed.

4. In a typewriting machine, the combination hammer, means operable bysaid key levers to effect the actuation of said hammer, means to returnsaid hammer after each printing operation, an electro-magnet to energizesaid hammer returning means. means actuable by the key levers to rendereflective the electro-magnet at each actuation of a key lever,

and means independent or the key levers to render said electro-magnetineirective after each printing operation of the hammer to preventheating of the electro-magnet it the return oi. thekey lever is delayed.

5. In a typewriting machine, the combination or key levers, a printinghammer, means operable by said key levers to eflect the actuation of thehammer, means to' return said printing hammer after each printingoperation, a solenoid having.

a plunger, means including a bar connected to said plunger whereby. thehammer returning means may be energized by the solenoid, 2. normallyopen switch electrically connected with said solenoid, means including aresilient element operable by the key levers to close said switch torender the solenoid efiective, and an adjustable device-on said bar tooperate and disengage the resilient element 01' the switch closing meansfrom the switch to effect the opening of the latter after each printingoperation of the ham:- mer.

6. In a typewriting machine, the combination of key levers, a printinghammer, means operable by said key levers to eflect the actuation of thehammer, spring actuated means to return said printing hammer, electricmeans to cook the spring actuated means, an element operable by the keylevers to render the electric means active at each depression of any oneofthe key levers, and means to automatically render said elementineffective after the spring actuated means has been cooked by theelectric means so as to render the latter ineffective while the activeone of the key levers is still operated to thus prevent heating of theelectric means.

7. In a typewriting machine, the combination of key levers, aselectively settable type carrier, means operable by said key levers toeffect the setting of said type carrier, a hammer to cooperate with saidtype carrier, means operable by said key levers to effect the actuationof said hammer, a spring, means operable by said spring to return saidhammer, means including an electro-magnet to energize said spring, meansincluding a switch operable by and upon each actuation of any one of thekey levers to render effective said electi e-magnet, and means toautomatically render the electro-magnet ineffective after it hasenergized said spring and while the key lever is still in its actuatedposition.

8. In a typewriting machine, the combination of printinginstrumentalities including two elements, namely a settable typecarrierandan element to cooperate with any one of the types to causethem to print, means operable by said key levers to eifect the settingof said type carrier, means to efiect the actuation of one of saidprinting elements toward the other to effect the printing, meansincluding a spring to return the operated printing element, electricmeans, means operable by said key levers to render the electric meanseffective to cook the means which includes the spring, at each actuationof any one of the key levers, and means whereby the electric means maybe rendered ineffective after the means including the spring has beencocked and while the active key lever is still in its actuated position.

ALFREDE; OSWALD.

